alexandersofm



Dec. 4, 1928. 1,694,302

E. F. w. ALEXAEIDERSON TRANSMISSION OF PICTURES Filed i- 25, 1928 v 2' Sheets-Sheet 1 Inventor-1 EF'nSI E WALeX andev'son,

wZZm/ by V His Attor-neg.

Dec. 4, 1928.

E. F. W. ALEXANDERSON TRANSMISSION OF PICTURES Filed Jan. 23, 1928 ZSheets-Sheet 2 Z5 /4 12 I l5 d 9 8 iii/fir /z ifl Z! i FLgA. ii /Z- Inventor-Q Ernst EW ALe xand e P500,

HLS Attorney.

Patented Dec. 4, 1928.

UNITED STATES PATENT QFF ICE.

ERNST F. W. ALEXANDERSON, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF 'NEW YORK.

TRANSMISSION OF PICTURES.

Application filed January 23, 1928. Serial No. 248,731.

My invention relates to the transmission of pictures, and has for its principal object the provision of an improved picture receiving apparatus which may be readily operated and controlled by those inexperienced in the use of such apparatus.

Various types of picture transmitting systems have been provided in the past. Many of these systems include a transmit-ting apparatus for scanning the elemental portions of the picture and producing electrical impulses which are proportional to the intensity or color of the light emitted by the successive elemental portions. and a receiving apparatus for converting these electrical impulses into light which may be applied to a sensitive film or other receiving element. In order to prevent distortion of the picture, it is essential that means be provided for establishing'synchronism between the moving parts of the transmitting and receiving apparatus. Thus when a sensitive film is employed to receive the picture, it is necessary that the movement of the picture be duplicated by that of the film. In accordance with my invention,

these results are produced by an improved apparatus and method of operation whereby the picture receiving or recording element is moved in one direction at a predetermined speed and is readily put into motion in another direction. My invention will be better understood from the following description when considered in connection with the'accompanying drawing and its scope will be pointed out in the appended claims.

v Referrmg t0 the drawing, Fig. 1 is a perspective view of a picture receiving apparatus constructed in accordance with my invention, and Figs. 2 to 4 illustrate various details of the apparatus of Fig. 1.

This apparatus comprises a rotatable drum 1 which supports the receiving film and is coupled to a driving'motor through gears 3 and 4, hollow shafts 5 and 6, and rods 7 and 8. Extending through the hollow'shafts 5 and 6 is a shaft 9 provided at its end with a brake pulley 10 and threaded at its central portion to engage'a' pair of nuts 11 and-12 which cooperate with the rods? and 8 and the shaft 9 to move the drum 1 along the axis of the shaft in a. direction dependent on the direction of the rotation of the motor 2. A. brake shoe controlled by a handle 14 is arranged to cooperate with the brake pulley 10.

shoe are in engagement with one another,

however. rotation of the shaft 9 is prevented and the drum 1 is moved along the axis of the shaft- 9 by the nuts 11 and 12 which are threaded on this shaft. along the axis of its rotation is thus readily started and stopped while the drum is rotating.

The drum 1 is mounted within a casing 15 provided with a hinged top and side cover 16 and is arranged to move past the eyepiece of a telescope 17 which extends into the casing15 and transmits light from a suitable source 18 to the recording element mount- '65 Movement of the drum ed on the drum 1. The light produced by-the impulses into light impulses but'it will of course be understood that any other suitable source of light may be utilized for this purpose.

Various means may be utilized for deter mining when synchronism is established between the rotation of the druml and the member on which the picture to be transmitted is mounted. One suitable means for-accomplishing this result is a contact disk 21 which is mounted on the hollow shaft 5, is provided with an'insulation segment 22-and is arranged to cooperate with a pair of brushes 23 connected to the amplifier 20 througha switch and a telephone 25 or other a suitable indicating device.

Assuming the picture transmitting apparatus to be providedwith means for producing and transmitting synchronizing impulses depending on the rotational speed of the memher 'on which the picture is mounted, these synchronizing impulses will produce 'an indication at the device'25at all times'except when they occur during the period of contact between the insulation segment 22 and the brushes 23, When the speedof the motor 2 is n so adjusted that, this period of contact always coincides with the synchronizing impulses no 1nd1cat1on is produced at the device 25 and the picture transmitting and receiving drums are rotating. at the same speed. chronislii between the axial movements of the transmittingandreceiving drums of course results froiirthe similarity in the construction of the transmitting and receiving apparatus. v I

What.I claimas new and desire to secure by Letters Patent of the United States, is: 1. A'picture receivin'g'apparatus including a rotatable member, a threaded member mechanically. coupled to said rotatable member 15 through frictionalcontact between said mem- 2'0 are moved with respect to one another.

bers, and means arranged to cooperate with said-threaded -member for moving said rotatable member along its axis of rotation when said rotatable and threaded members 2. A'picture receiving apparatus including a pair" of rotatable members mechanically coupled together through frictional contact therebetween, means for producing relative movement between said members, and means Syn- 1 responsive to said relative movement for causlng one of said members to be moved .along the rotational axis of said members.

3. A picture receiving apparatus including a movable member, a member arranged to be driven by said movable member through frictional contact between said movable and driven members, means for producing reladriven members, and means responsive to said relative motion for causing one of said members to be moved in a direction transverse to the movement of the other of said members.

4. A picture receiving apparatus including i relative movement for causing said rotatable member to be moved along its axis of rotation. In witness whereof, I have hereunto set my hand this 21st day of January, 1928.

ERNST F, W. ALEXANDERVSON.

' tive movement between said movable and 

